One of the problems when working with W3C XML Schema is the fact that it uses an XML syntax, which makes schemas verbose and hard to read. This article describes a compact text-based syntax for W3C XML Schema, called XML Schema Compact Syntax (XSCS). 

Reflection enables a programming language to inspect and modify its own code. XSLT, being expressed in XML, comes with this built in. This article shows how XSLT can be used to process XSLT to solve real problems. 

This article by Norman Walsh addresses the recent debate about the merits of XSL.